Automotive Embedded Computer Systems

Latest Advanced Technology and Tasks in Automobile Engineering

Seminar 4: Automotive Embedded Computing Systems

Jenna M. Eason

Investigate on one of the following systems/services and write a short paper on its purpose, function, and system structure.

I have chosen “immobiliser”.

An immobilizer is an electronic device fitted to an automobile, which prevents the engine from running unless the correct key, code, or token is present [1].  The primary purpose of this device to prevent theft and “hotwiring” of a vehicle.   This is achieved due to a tiny transponder most often embedded into the vehicles ignition key, which controls the immobilizer system.  The transponder contains a unique and unalterable identification code that corresponds to that particular vehicle.  Every time the key is inserted into the ignition, a radio frequency reader located in the steering column is triggered. As the ignition is turned, the reader is activated and sends out a wireless signal (unique binary code) to the transponder.  The signal powers up the transponder’s capacitor, allowing it to transmit its unique code back to the reader.  The reader is comprised of a very small antenna integrated with the ignition switch and the steering lock cylinder, and a transceiver, which is connected to a control module in the engine’s central computer.  The computer controls vital automotive functions, such as the ignition and fuel supply circuits [2].  The control module then compares this signal to the code stored in its memory.  If the two codes match, and the appropriate additional security challenges are passed, the control module enables the engine’s computer or the fuel pump relays.  If the codes do not match, an alarm indicator will show and the engine will not start [2]. To disarm the system, a special transponder key or code is required.  These systems arm automatically once a vehicle shuts down (called passive arming) [3].

One 1999 study reports that auto theft rates in Western Europe dropped by over 1/3 from a peak of 144,000 in 1993 to 95,349 in 1997 [2].  It is believed that this drastic decrease is the direct result of the introduction of Automotive Immobilizer Anti-Theft Systems in 1993.  Upon its introduction to the European market, the system became mandatory equipment on all new vehicles sold beginning in 1995 [2].

Following this success, factory and aftermarket immobilizer systems are now featured on many models sold throughout countries outside of Europe.  The companies employing this technology include Chrysler, Ford, Hyundai, and Toyota.  Aftermarket sales have also proved highly successful [2].   

Sources:

1. www.Wikipedia.com

2. http://www.theautochannel.com/news/press/date/19990601/press024256.html

3. http://www.absoluteautoguard.com/index2.php?option=com_content&do_pdf=1&id=4